Dispensers are commonly employed to deliver granular/particulate material, such as seasoning, colorants, concentrates, powdered mixtures, etc. For example, dispensers are used to add seasonings and flavorings to foods and/or beverages. Typically, seasonings such as table salt and ground pepper are dispensed from shakers comprising a single-chamber container or reservoir. The container may include an end cap comprising a plurality of apertures to allow the material to be dispensed upon inverting and agitating the shaker. The size and number of apertures will vary with the type of material to be dispensed. For example, a dispenser for table salt will typically have fewer apertures than, for example, a pepper dispenser inasmuch as the density and concentration of table salt is such that smaller quantities are desired (i.e., with each oscillation of the container.) Generally, a dedicated dispenser with the appropriately sized/numbered apertures will be employed for each material to control the dispensing rate. While the size and number of apertures can control the flow rate of material, the user must monitor other variables such as the length of time, number of oscillations, etc., to accurately control the quantity of dispensed material.
Many prior art dispensers address the need to deliver a controlled or preset amount of material by employing two or more chambers and a delivery tube. A first chamber forms a material reservoir while a second chamber is calibrated for measuring the material. The chambers are typically stacked, one above the other or in tandem. The delivery tube communicates with the measuring chamber at one end, extends through the reservoir, and at the opposite end communicates with the apertures of the dispenser. See, e.g., Abbott U.S. Pat. No. 1,707,967; Trautvetter U.S. Pat. No. 1,763,449; and Gordon U.S. Pat. No. 2,644,616.
Yet another metered material dispenser is disclosed in Jones et al. U.S. Pat. No. 6,269,983. Therein, a measuring cup is disposed in one end of the dispenser for receiving material when the dispenser is face-up, i.e., with the dispensing end facing upwardly. When the dispenser is inverted, material flows into a passageway defined by and between co-axial, cylindrical containers. Once in the passageway, the material flows downwardly and out of a dispensing end or diffuser. The configuration and spacing of the containers restricts dispensing of excess material, even when agitated. This Jones patent is commonly assigned with the present application and is herein incorporated by reference.
Eckman U.S. Pat. No. 4,961,521 discloses an adjustable metered dispenser useful for delivering seasonings such as salt and pepper. Eckman's dispenser comprises two chambers arranged in seriatim. The first chamber is a material reservoir and the second chamber is a measuring chamber. Eckman's dispenser exhibits an ability to close the metering chamber from the reservoir chamber when the material is dispensed. Thus, in order to avoid over-dispensing, the user must be sure that the passageway between the two chambers is closed.
Krupic U.S. Pat. No. 5,169,049 discloses a dispenser for seasonings, such as salt and pepper. The shaker comprises three chambers: a material reservoir chamber, a measuring chamber and a dispensing chamber. The reservoir chamber is disposed between the measuring chamber and the dispensing chamber while a delivery tube communicates with the measuring chamber and the dispensing chamber. When the dispenser is not in use, the measuring chamber faces downwardly. During use, the dispenser is inverted, and the dispensing chamber is filled with the material from the measuring chamber. The material must then be dispensed by shaking the dispenser in the inverted position to evacuate the material from the dispensing chamber via a plurality of apertures. In order to prevent over dispensing, one embodiment of the device includes shake-back guards within the reservoir chamber.
Peterson et al. U.S. Pat. No. 7,143,909 shows a dispenser capable of dispensing a variable quantity of a material or for dispensing a variety of different materials. This Peterson application is commonly assigned with the present application and is herein incorporated by reference.